Re-normalisation of 17/4 PH

[ProductionEngineerUK]

Recently a supplier misread a drawing and heat-treated a batch of 17/4 ph components to H1025 instead of H900.
Shouldn't this be a straight forward case of re-normalising the material, and following the correct heat-treat specification to achieve H900.
Or are there other factors that should be a consideration?

Thanks in advance for any information.

 

[metengr]

To correct the material, the 17-4 would require a re-solution anneal heat treatment at 1900-1950 deg F followed by air cooling. The aging for H900 would be heating to 900 deg F and holding for 1 hour at temperature.

The problem is distortion if the components are in a final machined condition. To prevent further problems the heat treatment should be in a reducing atmosphere to avoid further oxidation during the anneal treatment.

Make sure you get all heat treatment information from this vendor. if they can misread a drawing they can misread controls for heat treatment.

 

[EdStainless]

Typically you would re-anneal in a dry hydrogen atmosphere to preserve the surface condition of the parts.
We use 1900-1925F, you then have to cool to below 90F before you start the aging treatment.

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P.E. Metallurgy, Plymouth Tube

 

[JamesCKelly]

H900 has rather low toughness & is susceptible to SCC. Might suggest you consider H950 after re-solution annealing. Tensile strength is not everything.